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jextract error => DTLJ failure? [message #7675]

Sat, 22 November 2008 18:40

Eclipse User

WInXP; IBM JVM:

java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build
pwi32dev-20070511 (SR5))
IBM J9 VM (build 2.3, J2RE 1.5.0 IBM J9 2.3 Windows XP x86-32
j9vmwi3223-20070426 (JIT enabled)
J9VM - 20070420_12448_lHdSMR
JIT - 20070419_1806_r8
GC - 200704_19)
JCL - 20070511

Rather often when running "jextract" (from that JVM) to create the zip
necessary for DTLJ, jextract reports (these are all the cases):

could not read J9Class (464 bytes) at 059B5E68

could not read J9Class (480 bytes) at 05C03E68

could not read J9Class (456 bytes) at 063EAE60

could not read J9Class (464 bytes) at 05BC6E90

could not read J9Class (456 bytes) at 05687E88

could not read J9Class (464 bytes) at 05CEAE90

What's up with that?

I also often have the result that MAT+DTLJ reports no memory usage by
anyone except the class-loaders; if that bogus report occurs, it has
always (so far) been the case that one of the above errors in jextract
had occurred. (But some of the jextract errors did not seem to lead to
DTLJ errors.)

any ideas?

thanks,
Paul

Re: jextract error => DTFJ failure? [message #7718 is a reply to message #7675]

Mon, 24 November 2008 05:24

Eclipse User

I suggest you try using the latest IBM VM.

Please see the following link - the latest versions of the IBM virtual
machines are available here:
http://www.ibm.com/developerworks/java/jdk/index.html

For the Windows platform the VM is not available separately, but is
available combined with an Eclipse environment:

IBM Development Package for Eclipse
This is the IBM Development Package for Eclipse. It contains a
ready-to-run Java development environment consisting of the Eclipse IDE
and the IBM Java runtime. You can use this package to develop, test and
run your Java applications. Downloads are available for Windows and Linux
operating systems on Intel 32-bit platforms.

We haven't done much testing with back levels of the VM and dumps from old
VMs won't have accurate GC root support, so GC roots will be guessed and
some may be missing and some bogus roots may be found with dumps from old
VMs.

This is why we say to use IBM JDK 1.4.2 SR12, 5.0 SR8a and 6.0 SR2 or
later.

Re: jextract error => DTFJ failure? [message #7778 is a reply to message #7718]

Mon, 24 November 2008 21:34

Eclipse User

Andrew Johnson wrote:
> I suggest you try using the latest IBM VM.
>
....
> We haven't done much testing with back levels of the VM and dumps from
> old VMs won't have accurate GC root support, so GC roots will be guessed
> and some may be missing and some bogus roots may be found with dumps
> from old VMs.
>
> This is why we say to use IBM JDK 1.4.2 SR12, 5.0 SR8a and 6.0 SR2 or
> later.
>

OK, that seemed to do the trick, thanks. (I should have paid more
attention to the SR level and its importance.) Now I have as follows,
and the MAT + DTLJ seems to be working reliably:

java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build
pwi32devifx-20081023a (SR8a + IZ34138))
IBM J9 VM (build 2.3, J2RE 1.5.0 IBM J9 2.3 Windows XP x86-32
j9vmwi3223ifx-20080811 (JIT enabled)
J9VM - 20080809_21892_lHdSMr
JIT - 20080620_1845_r8
GC - 200806_19)
JCL - 20081016a

thanks,
Paul

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